code: def load(root_path):
      file_path = os.path.join(root_path, "multi_mnist_uint8.npz")
      if os.path.exists(file_path):
          data = np.load(file_path, allow_pickle=True)
          return data["x"], data["y"]
      else:
          # Set RNG to known state.
          rng_state = np.random.get_state()
          np.random.seed(681307)
          mnist = load_mnist(root_path)
          print("Generating multi-MNIST dataset...")
          x, y = mk_dataset(60000, mnist, 2, 50)
          # Revert RNG state.
          np.random.set_state(rng_state)
          # Crude checksum.
          # assert x.sum() == 883114919, 'Did not generate the expected data.'
          with open(file_path, "wb") as f:
              np.savez_compressed(f, x=x, y=y)
          print("Done!")
          return x, y
  
file_path: pyro/pyro/contrib/examples/multi_mnist.py
imports: import os
  import numpy
  from PIL import Image
  from pyro.contrib.examples.util import get_data_loader
label_desc: Use image node_id 6 for calling a global function with example usage: load(root_path) and returns: data,  data, x,  y